﻿/**
 * @param {string} s
 * @return {string}
 */
var toLowerCase = function (s) {
    return s.toLowerCase();
};

var toLowerCase = function (s) {
    const sb = [];
    for (let ch of s) {
        if (ch.charCodeAt() >= 65 && ch.charCodeAt() <= 90) {
            ch = String.fromCharCode(ch.charCodeAt() | 32);
        }
        sb.push(ch);
    }
    return sb.join('');
};